TS-SW841D subwoofers is designed to provide wider installation options for a broad range of vehicles. These "Shallow-Mount" subwoofers feature multiple patent-pending features to deliver the big bass performance of a full-size subwoofer, but in a compact design that can be installed either behind or under seats depending on the type of vehicle. The mounting depth is just 2-1/2" less than half a typical subwoofer in this class.